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EMT 212 ANALOGUE ELECTRONIC II
TUTORIAL #2
EMT 212 ANALOGUE ELECTRONIC II
TUTORIAL #2
Part A (Real op-amp & parameters)
Q1.
300K
IF
15K 
RF
_
R1
Iin
741
I1
I2
Vs
741
+
Vo
Figure 1
Answer the questions below based on Figure 1. Given IBIAS=30 pA, IOS= 3 pA and
Rin= 14.29 k 
a. Derive output voltage equation when Vs is zero
b. Determine I1 and I2
c. Determine the offset voltage and output error voltage developed by the input
offset current when Vs is zero?
d. According to part (d) a compensating resistor needs to be added to the noninverting input, what size should it be? Determine output voltage.
Q2.
Figure 2 shows the op amp circuit and it input waveform.
0.01F
V(volt)
10 k 
_
+2.5
vin
vout
+
(a)
Figure 2
t
-2.5
(b)
EMT 212 ANALOGUE ELECTRONIC II
TUTORIAL #2
Determine:
a. Slew rate of the op-amp
b. Time rise
c. What is power bandwidth of the op amp?
Part B (Constant Gain Multiplier, Controlled Sources, Instrumentation Amp)
Q1.
Figure 1
Figure 1 is a schematic diagram of a multistage amplifier. Answer questions
below by referring to the schematic. Use root means square (rms) value in
calculation.
i)
ii)
iii)
iv)
Q2.
i)
ii)
Calculate the output voltage, Vout if the input voltage given is
300 2 sin 2100tmV .
What will happen when R6 opens? Draw the input and output waveforms.
Determine new output voltage, Vout if the value of R6 changes to 100kΩ.
Name the type of multistage amplifier shown in Figure 1.
Controlled sources can be categorized based on its circuit configurations. It can be
configured as voltage/current to control current/voltage or vice versa. Answer the
questions below.
Name 4 type of controlled sources configuration circuit.
Design a VCVS amplifier to meet the specifications given.
Inverting Configuration
Closed Loop Gain, Acl=32
Input Resistance, R1/i=1kΩ
EMT 212 ANALOGUE ELECTRONIC II
TUTORIAL #2
iii)
Design a VCIS amplifier to meet the specifications given.
iv)
Non-Inverting Configuration
Closed Loop Gain, Acl=63
Input Resistance, R1/i=2kΩ
Design an ICVS amplifier to meet the specifications given.
Inverting Configuration
Input Current =1 mAp-p
Output voltage =6Vp-p
v)
Design an ICIS amplifier to meet the specifications given.
Inverting Configuration
Input Current =2 mAp-p
Output Current =66 mAp-p
R2 =1kΩ, RL =1kΩ
Q3.
Figure 2
Based on the circuit shown in Figure 2;
i)
ii)
iii)
Derive the equation to calculate overall closed loop gain,
Vout
of the
V1  V2
instrumentation amplifier (IA).
Closed loop gain of the IA is set to 40dB and all internal resistances have
equal value of 2kΩ, determine the value of external resistance, aR.
Draw the IA output waveform based on the specifications below.
EMT 212 ANALOGUE ELECTRONIC II
TUTORIAL #2
V1  100sin 2 1000tmV
V2  80sin 2 1000tmV
DC Offset   5V
Part C (Frequency Response & Feedback Circuit)
Q1.
Consider a series-shunt feedback amplifier is having the open-loop gain is
A  100000 and the closed-loop gain is A f  80 . Given the input and output
resistances of the basic amplifier are Ri  1.5k and Ro  50k , respectively.
Determine the input and output resistance of the circuit.
Q2.
A series-series feedback amplifier has a following parameters:
Open-loop gain, A  250 ,
Input resistance, Ri  1.5k ,
Output resistance, Ro  33k ,
Feedback factor,   1 / 18 ,
Open loop bandwidth, BWol =10 Hz,
Calculate;
(i)
closed-loop gain, AF
(ii)
input feedback resistance, RiF
(iii) output feedback resistance, RoF
(iv)
close-loop bandwidth, BW cl
Q3.
Based on Figure 4, assumes the op-amp is ideal
R2
R1
-15V
-
Vin
Vout
Rs
+
+15V
(i)
RL
Find an expression for the feedback factor,  .
EMT 212 ANALOGUE ELECTRONIC II
(ii)
(iii)
TUTORIAL #2
If the open-loop voltage gain, A =2500, find R2 R1 to obtain closed-loop
voltage gain, AF of 30.
If A decreases by 25%, what is the corresponding decrease in AF ?